Motor fuel and method of preparing same



Patented Nov. 27, I934 UNITED STATES PATENT or 1,982,277 F ICE 1,982,277 MOTOR FUEL AND METHOD OF PREPARING SAME Y Carl Winning, Elizabeth, N. J., assignor, by mesne assignments, to Gasoline Antioxidant Company, Wilmington, DeL, a corporation of Delaware No Drawing, Application April 24, 1931, Serial lWo. 532,707

industry that low boiling hydrocarbon oils such naphtha;

Naphthas containing large quantities of gum, or constituents tending to form gum during storage, are objectionable for many purposes, such as for motor fuels, light solvents, etc. Recently a careful study of gum formation has been made by petroleum chemists-and several organic compounds have been found which, when added n small quantities to low boiling hydrocarbon oil, will retard or inhibit gum formation for periods of time varying with the nature of the compound, the oil, and other conditions.

The usual test for such gum forming constitucats is known as the copper dish method and is described on page 96 of the United States Bureau of .MinesTechnical Paper No. 323 D, revised October 21, 1927. The result of this test is expressed in milligrams of gum left in the dish on evaporation of 100 cc. of naphtha.

Another testing method consists of adding oxygen under pressure to the sample of the low boiling hydrocarbon oil to be tested in a closed vessel, and then keeping the oil at elevated temperature of say 100 C. under a pressure of oxygen of say 100 lbs. per square inch. For a certain time the pressure remains practically constant,

then it begins to drop suddenly. This drop is observed on a pressure gage. The period of time during which no. pressure drop is observed is called the induction period. The

longer this induction period, the better is the particular oil tested, and the less likely it is to form gum during storage.

An approximate quantitative relation for the gum inhibiting power of a certain inhibitor may .50 be expressed by the following equation:

SB 1 I.P.B--X6 where I. P.=inhibiting power S=i nduction period of solution ,B=induction period of blank or solvent C=concentration of the inhibitor in by weight. v

The test just described quicker and more 0 reliable, and gives more readily reproducible data, than the copper dish method. The I. P. number of an inhibitor will accordingly be used herein as a measure of its value. It will be understood, however, that the inhibitors of the present invention may be rated according to the copper dish method, or other suitable method, and will show a corresponding value. Moreover, these inhibitors .are effective in actual storage tests, that is, when added to naphtha stored in thetanks of refineries or distributors. The

oxidation test described herein gives an accelerated indication ofthe performance to be expected during storage.

I have discovered that aromatic nitroso compounds and such mixed derivatives as nitroso phenols and nitroso amines are good "gum inhibitors. When mixed derivatives such as nitroso amines or nitroso phenols are used it is preferable to have the amino or hydroxyl in the para or ortho position to the nitroso group. Many suitable nitroso derivatives exist such as dinitroso resorcinol, nitrosonaphthol, para-nitroso dimethyl aniline; alpha-nitroso beta-naphthol, beta-nitroso alpha-naphthol, etc. Some of the aromatic derivatives containing a nitroso group may also impart color to the naphtha, and dyes containing the nitroso group may also be used.

Compounds of the class described above will give an eflicient protection against gum formation in a gasoline during ordinary storage for a long period of time when added in amounts of from 0.0005 to 0.1% by weight of the oil. The necessary amounts are best determined empirically. Compounds of the type described are in general sufiiciently oil soluble and may be readily distributed uniformly throughout even large bodies of oil by simple mixing. If desirable they may be dissolved in benzene or other suitable solvent from which they will not be readily precipitated by access of moisture. The solution so prepared may be mixed with the oil.

-The following example will illustrate the improvement obtained in gum inhibitors by the introduction of a nitroso group. Dimethyl ani line is a comparatively poor gum inhibitor which has an I. P. number of 35. Para-nitroso dimethyl aniline, on the other hand, is a good gum inhibitor having an I. P. number of 250.

My invention is not to be limited by any theory nor by the examples given as illustrations but only'by the following claims in which it is {my intention to claim all novelty inherent in my invention.

I claim:

1. A motor fuel. comprising cracked gasoline normally tending to deteriorate and farm gum, and containing a small quantity of a gum inhibiting agent selected from the group consisting of dinitroso polyhydroxy benzenes, nitroso naphthols wherein the nitroso .and hydroxyl groups are on adjacent carbon atoms, and a.

nitroso aniline.

2. The method of preserving cracked hydrocarbon distillates which deteriorate and develop gum on storage, by incorporating therein a small proportion of an organic reducing agent selected from the. group consisting of dinitroso polyhy- 'droxy benzenes, nitroso naphthols wherein the nitroso and hydroxyl groups are on adjacent carbon atoms, and a nitroso aniline.

3. A motor fuel comprising cracked gasoline which normally tends to deteriorate and form gum upon storage and containing 'a small quantity of a'nitroso aniline in quantity suflicient to retard such deterioration and gum formation.v

4. A motor fuel comprising cracked gasoline normally tending to deteriorate and forin gum upon storage and'containing a small quantity of a nitroso naphthol selected from the group consisting of alpha-nitroso-beta naphthol and beta-nitroso-alpha naphthol.

5. A cracked naphtha normally tending to form gum during storage and stabilized against gum formation by the addition of 0.0005 to 0.1 

